Exploring momentum, temperature and doping dependence of mass renormalization in Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$

Among the many novel aspects of cuprate high-temperature superconductors, one of the most important is that the parent undoped state of these materials is a strongly correlated Mott insulator. How these correlations impact or contribute to the superconducting state in the doped materials remains a critical aspect of understanding the mechanism of high temperature superconductivity. From a newly developed technique of studying self-energy in Angle-Resolved Photoemission Spectroscopy (ARPES), we explore the mass enhancement at low frequency as a function of momentum, temperature and doping. Comparing our result to the other measures such as specific heat and quantum oscillation, we show that ARPES can be a highly useful tool for effective mass measurement.